We compute invariant Lagrangian tori of analytic Hamiltonian systems by the parameterization method. Under Kolmogorov’s non-degeneracy condition, we look for an invariant torus of the system carrying quasi-periodic motion ...

In the present paper we consider the case of a general $\cont{r+2}$
perturbation, for $r$ large enough, of an a priori unstable
Hamiltonian system of $2+1/2$ degrees of freedom, and we provide
explicit conditions on it, ...

We consider perturbations of integrable area preserving non twist maps of the annulus those
are maps in which the twist condition changes sign These maps appear in a variety of applications notably
transport in atmospheric ...

We consider the existence and effective computation of low-dimensional (less independent frequencies than degrees of freedom) invariant tori of a near-integrable system. Lindstedt method is a systematic procedure to compute ...